Safety of Spinal Cord Stem Cell Transplant Established

Medical Studies/Trials, July 19, 2006

According to University of California – Irvine researchers, transplanting stem cells is not harmful and can serve as a therapeutic approach for the treatment of severe spinal cord injury.

The study conducted by Hans a UCI neurobiologist, and his colleagues at the Reeve-Irvine Research Center confirms previous findings by Hans' lab; that replacing a cell type lost after injury improves the result after spinal cord injury in rodents. Identical data published by four other laboratories in the world show that rats with either mild or severe spinal cord injuries that were transplanted with using stem cells as a treatment suffered no visible injury or ill effects as a result of the treatment itself.

In 2005, Hans' lab was the first to persuade stem cells to become highly pure specialized cells known as oligodendrocytes. The cells are imperative for the maintenance of electrical conduction in the central nervous system and also serve as the raw materials of myelin which acts as an insulation for nerve fibers. Paralysis can result when myelin is lost through disease or injury.

The current study, just like the original, exhibited that rats suffering from severe spinal cord injury injected with oligodendrocytes seven days after the injury, had the cells migrate to the proper sites within the spinal cord and wrap around damaged neurons, forming new myelin tissue.

In comparison, rats that were only slightly impaired showed no change in walking ability after transplantation or an increase or decrease in myelin generation. Hans says this is due to the fact that no loss of myelin occurred. Thus, any treatment targeted at regenerating myelin would have no effect because the animals were able to recover motor functions on their own, due to the minor nature of the injuries. It is important to note that although the treatment did was not able to provide ay benefit, it also did not cause any harm. Scientists decided to examine further and found no signs of damage to the tissue surrounding the spinal cord, thus demonstrating that no damage had occurred due to transplantation in the animals.

"Establishing the safety of implanted stem cells is crucial before we can move forward with testing these treatments in clinical trials," said Hans an associate professor of anatomy and neurobiology and co-director of UCI's Stem Cell Research Center. "We must always remember that a human clinical trial is an experiment and, going into it, we need to assure ourselves as best as we can that the treatment will not cause harm. This study is an important step in that direction."

Hans is working with Geron Corp. to bring this treatment for acute spinal cord injury into Phase I clinical trials within the next year.

"Our biggest safety concern was that in the case of a severe injury, any harm the stem cell-derived treatment could cause would be masked by the injury itself," Hans said. "In this study, we can see in animals that are only slightly injured that the transplantation does not cause visible harm and the injury is not hiding any damage the cells may have caused to the spinal cord or the surrounding tissue."

UCI is a premier center for stem cell research in California. The university announced last week that it had received a $10 million gift from Bill and Sue in support of stem cell research, including matching funds to construct an $80 million Stem Cell Research Center facility.